In general, a liquid crystal display device includes a TFT substrate in which a plurality of thin film transistors (hereinafter referred to as “TFTs”) are formed, a counter substrate facing the TFT substrate, and a liquid crystal layer provided between the TFT substrate and the counter substrate. A sealing member is provided between the TFT substrate and the counter substrate to bond the TFT substrate and the counter substrate together, and enclose a liquid crystal layer.
The liquid crystal display device also includes a display region in which a plurality of pixels are disposed and which contributes to display, and a non-display region which surrounds the display region. The sealing member is disposed in the non-display region.
The TFT substrate includes a glass substrate on which the TFTs etc. are formed. On the glass substrate, an interlayer insulating film is formed to cover the TFTs, and a pixel electrode made of indium tin oxide (ITO) is formed on the surface thereof. The interlayer insulating film is made of an organic insulating film of, e.g., a photosensitive acrylic resin etc.
Patent Document 1 discloses, in order to improve the bond strength between a sealing member and a TFT substrate, removing an interlayer insulating film made of an organic insulating film in a region in which the sealing member is formed to expose a glass substrate or an inorganic insulating film (a passivation film, a gate insulating film, etc.) which constitutes the TFT substrate.
Patent Document 2 discloses, as illustrated in FIG. 53, that a TFT substrate 100 is provided with, on the flat surface of an overcoat film 109 covering a TFT 105 and a signal line 107, a protective film 110 overlapping a region slightly larger than a region in which the signal line 107 and a drain electrode 103 of the TFT 105 overlap with each other, and the protective film 110 is made of the same material (ITO) as the pixel electrode 104. With this configuration, even if the overcoat film 109 has damage, a discontinuity of the signal line 107 does not occur under the defect.